HD Tune — Transfer rates
We'll kick off the festivities with HD Tune, which lets us take a closer look at sequential transfer rates and random access times. The results in the graphs have been color-coded for easy reading, with the Laptop Thin SSHD appearing in a different shade of green than the other Seagate drives. To keep the bar charts from turning into multi-colored rainbows, we've dressed all the solid-state drives in gray.

The SSDs have also been omitted from the line graphs below. They have much higher transfer rates than the mechanical drives, which throws off the scale and makes things harder to read.

Our average read speed results show a stark contrast between mechanical and solid-state storage. The hybrids are in the same league as the mechanical drives, likely because this test is entirely sequential in nature. The Laptop Thin SSHD is actually 2MB/s slower than its Momentus XT 750GB predecessor here.

Check out the difference in transfer rate profiles highlighted by the line graph. Like virtually all of the other drives, the Laptop Thin SSHD exhibits a slow decline in transfer rates as the test progresses through the disk. However, there's an odd jump in performance at about the 97% mark. A similar blip is visible in the write speed results.

If we focus on the average speed across the entire disk, the Laptop Thin SSHD again finds itself well behind the solid-state drives but competitive with the old Momentus XT 750GB. It doesn't look like the Laptop Thin's write-caching capability is being exploited by this test.

HD Tune's burst speed test targets a different sort of drive cache: the DRAM memory commonly found on mechanical drives, hybrids, and even SSDs. This DRAM cache weighs in at 64MB on the Laptop Thin SSHD, which is double what you get on either Momentus XT.

Solid-state drives don't always fare well in this test, perhaps because they can use their caches differently than mechanical drives. The Laptop Thin doesn't look so hot either; its burst speeds are faster than those of the first-generation Momentus XT but much slower than those of the second-gen model.